Made of the highest quality hand-spun aluminum, Jo-Ral mutes are designed and tested to perform evenly in all registers. Alternative materials used on the bottom of the mute create varying sound characteristics for special effect, giving musicians the freedom of artistic expression. Multi-propose all-aluminum mutes provide a bright muted sound, while brass-bottom mutes impart a slightly warmer, confidential sound ideal for smaller settings. For a darker, more mellow effect, copper-bottom mutes are the perfect choice. And all-copper mutes create a deep, rich, sound. Jo-Ral mutes also feature neoprene-enhanced composite cork pads that provide extra durability. The result is a more pliable cork that grips well and doesn"t dry out, become brittle or break off - so it lasts longer while easily accommodating fine adjustments for a perfect fit.